JP2011223207A - Radio device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio device and an audio control method thereof which implement a countermeasure for a short buzzing noise during voice transmission in duplex operation.SOLUTION: A VOX 56 detects the presence of a voice signal output from a received voice output section 71 of a voice codec 70a. A receiver amplifier 52a continues to output a mute signal to a receiver 51. The VOX 56 outputs an unmute signal to the receiver amplifier 52a when detecting a voice signal. The receiver amplifier 52a of a headset 50 unmutes audio output from the receiver 51 when the unmute signal is input from the VOX 56. The VOX 56 does not output the unmute signal to the receiver amplifier 52a when no voice signal is detected. The receiver amplifier 52a of the headset 50 continues to output a mute signal to the receiver 51 as long as no unmute signal is input from the VOX 56.

Description

  The present invention relates to a radio device of a time division multiple access system (hereinafter referred to as a TDMA system), which is a system that uses a single communication frequency divided by a plurality of channels in time, and in particular, makes a call alternately with a partner. The present invention relates to a radio and a voice control method for the radio.

  A wireless device that makes a call alternately with a communication partner is divided into a time zone for transmitting voice (hereinafter referred to as a voice transmission time zone) and a time zone for receiving voice (hereinafter referred to as a voice reception time zone). Unlike a conventional analog radio that transmits radio waves continuously in a voice transmission time zone, a TDMA radio that uses one communication frequency for transmission and reception differs from a conventional analog radio that transmits a radio wave as shown in the frame configuration of FIG. Even in the transmission time zone, radio waves are transmitted intermittently because switching between transmission and reception or reception waiting is performed in a time division manner.

  A frame structure of the TDMA system when one communication frequency is used for transmission and reception will be described. The frame configuration shown in FIG. 5 is an example in which one communication frequency is divided into four channels and used in time, and channels 1 to 4 are one basic frame. In such a frame configuration, when the length of the basic frame is set to 4 channels (40 ms) and the transmission time and the reception or reception wait time (hereinafter referred to as reception / standby time) are repeated at a ratio of 1: 3, Transmission is 1 channel (10 ms), and reception / standby is 2 to 3 channels (30 ms). That is, in one communication frequency, when transmission transmission time of 10 ms elapses, switching to reception / standby is performed, and when reception / standby time of 30 ms elapses, switching to transmission is performed.

  By repeating transmission and reception / standby in the voice transmission time period in this way, the receiver and speaker lines (+ ,-) Induces a current, and DC fluctuations occur in the audio signals of the receiver and the speaker. FIG. 6 shows the relationship between the transmission timing and the direct current fluctuation that occurs in synchronization with the transmission timing. This DC fluctuation generated in the audio signal of the receiver or the speaker is heard as an unpleasant “buzzing sound” for the user. The “buzzing sound” is particularly unbearable for a headset user who is putting the receiver on his ear. Therefore, when a user's voice is input and transmitted from the headset, the voice output from the receiver is muted (stopped).

  A description will be given of a TDMA type radio apparatus in the case where one communication frequency according to a conventional embodiment is used for transmission and reception.

  First, the configuration of a TDMA radio 100 according to a conventional embodiment will be described with reference to FIG. Since the wireless device 100 is a wireless device that makes a call alternately with the other party, the wireless device 100 is usually composed of two wireless devices 100 as shown in FIG. The wireless device 100 includes a wireless device body 10, an antenna 20, a speaker 30, a handset 40, and a headset 50. The handset 40 and the headset 50 are attached with a microphone for inputting sound and a receiver for outputting sound. In addition, the speaker 30, the handset 40, and the headset 50 do not have to be attached to the radio main body 10, and only one or two of them may be attached. The radio device main body 10 is a device that outputs audio signals received from other radio device main bodies 10 via the antenna 20 to the speaker 30, the handset 40, and the headset 50. The radio main body 10 is a device that outputs an audio signal input from the microphone of the handset 40 or the headset 50 to another radio main body 10 via the antenna 20. The speaker 30 is a device that converts an audio signal input from the wireless device body 10 into sound and outputs the sound at a volume that can be heard around. The handset 40 is used by the user in his / her hand. The handset 40 converts the voice input from the microphone into a voice signal and outputs the voice signal to the radio main body 10, and converts the voice signal input from the radio main body 10 into voice. And output to the receiver. The headset 50 is used by being worn on the head. The headset 50 converts voice input from the microphone into a voice signal and outputs the voice signal to the radio main body 10, and converts the voice signal input from the radio main body 10 into voice. Device that outputs to the receiver.

  Next, a functional configuration of the voice input / output unit 200 that performs voice input / output processing in the wireless device 100 according to the conventional embodiment will be described. FIG. 8 shows a functional configuration of the voice input / output unit 200. The audio input / output unit 200 includes a speaker unit 30, a handset unit 40, a headset unit 50, and an audio codec 70. The speaker unit 30 corresponds to the speaker 30 shown in FIG. 7 and includes a speaker 31 and a speaker AMP 32. The handset unit 40 corresponds to the handset 40 shown in FIG. 7, and includes a receiver 41, a receiver AMP 42, a PTT (Push To Talk) switch 43, a microphone 44, and a microphone AMP 45. The headset unit 50 corresponds to the handset 50 shown in FIG. 7 and includes a receiver 51, a receiver AMP 52, a microphone 53, a microphone AMP 54, and a PTT switch 55. The speaker AMP32, receiver AMP42, microphone amplifier 45, receiver AMP52, and microphone amplifier 54 are amplifiers that amplify audio signals. The PTT switch 43 is a switch that is “ON” when the user inputs a sound from the microphone 44 and is “OFF” when the input of the sound is finished. Similarly, the PTT switch 55 is also a switch that is “ON” when the user inputs a sound from the microphone 53 and is “OFF” when the input of the sound is finished. The audio codec 70 is a device that performs encoding (hereinafter referred to as “encoding”) or decoding (hereinafter referred to as “decoding”) on the audio signal received by the wireless device main body 10, and performs transmission and reception with the counterpart wireless device 100. is there. The audio codec 70 includes a reception audio output unit 71, a handset PTT input unit 72, a handset microphone input unit 73, a headset microphone input unit 74, and a headset PTT input unit 75.

  In such an audio input / output unit 200, when the audio signal received by the radio main unit 10 is decoded by the audio codec 70, the received audio output unit 71 passes the speaker 31 via the speaker AMP32 and the receiver AMP42. Are output to the receiver 41 and the receiver 51 via the receiver AMP52. When the PTT switch 43 of the handset 40 is turned “on” and a handset PTT signal is input to the handset PTT input unit 72 of the audio codec 70, the audio signal output from the microphone AMP 45 is transmitted from the handset microphone input unit 73 to the audio codec 70. Is encoded and transmitted to the wireless device 100 on the other side. The other party's wireless device 100 receives this handset PTT signal, and the other party stops inputting voice. In this way, the handset 40 can perform an alternate call. Audio input from the microphone 44 of the handset 40 is converted into an audio signal by the microphone 44 and output to the handset microphone input unit 73 via the microphone AMP 45.

  Audio input from the microphone 53 of the headset 50 is converted into an audio signal by the microphone 53 and output to the headset microphone input unit 74 via the microphone AMP54. A headset PTT signal output from the PTT switch 55 when the PTT switch 55 of the headset 50 is “ON” is output to the headset PTT input unit 75 and the receiver AMP 52 of the audio codec 70. In this state, the audio signal output from the headset AMP 54 is input from the headset microphone input unit 74 to the audio codec 70, encoded, and transmitted to the counterpart radio device 100. When the other party's radio 100 receives the transmitted voice signal, the other party outputs the voice from the receiver 51. In this way, the handset 40 can perform an alternate call. The receiver AMP 52 of the headset 50 includes a mute terminal. When a headset PTT signal (hereinafter referred to as a mute signal) is input from the mute terminal, the audio signal output to the receiver 51 is muted. Note that the handset PTT signal output from the PTT switch 43 when the PTT switch 43 of the handset 40 is “ON” is not output to the receiver AMP 42 like the headset PTT signal. The reason for this will be described later with reference to FIG.

  In the audio input / output unit 200 as described above, the speaker unit 30, the handset unit 40, and the headset unit 50 perform transmission and reception of audio signals based on the communication form. There are two types of communication modes: half-duplex voice communication (hereinafter referred to as simplex call) in which communication is performed from one side in two-way communication, and full-duplex voice communication (hereinafter referred to as “single-line communication”) in which communication is performed simultaneously from both sides. There is a form). Hereinafter, the flow of voice communication in the simplex and duplex calls of the wireless device 100 will be described.

  With reference to FIG. 9, the voice communication of the headset 50 in a simplex call will be described. In simplex communication, as shown in (1) and (2) of FIG. 9, a voice signal to be transmitted (transmitted voice) and a voice signal to be received (received voice) are alternately communicated through one communication line. As shown in (4), the PTT switch 55 is turned “ON” in the case of (1) “transmitted voice”, and in the case of (2) “received voice”, as shown in (4). The PTT switch 55 is “off”. Therefore, when the PTT switch 55 in (4) is “ON”, a mute signal is output from the PTT switch 55 to the receiver AMP 52, and the audio output of the receiver 51 in (5) is “OFF”. Further, when the PTT switch 55 in (4) is “off”, no mute signal is output from the PTT switch 55 to the receiver AMP 52, so that the audio output of the receiver 51 in (5) is “on”. Thus, even if the transmission timing of (3) occurs in the “transmission voice” time zone (voice transmission time zone) of (1), the voice output of the receiver 51 of (5) is set to “off”. Therefore, measures against “sounding noise” due to DC fluctuations occurring at the transmission timing are taken.

  The voice communication of the handset 40 in duplex communication will be described with reference to FIG. In duplex communication, as shown in (1) and (2) of FIG. 10, the voice signal to be transmitted (transmitted voice) and the voice signal to be received (received voice) are alternately communicated even if they are on separate communication lines. The However, since the transmission voice of (1) and the reception voice of (2) are different communication lines, the transmission voice of (1) is always in the voice transmission time zone. For this reason, transmission timing always occurs as shown in (3). Accordingly, even when a mute signal is output from the PTT switch 43 of the handset 40 to the receiver AMP 42 during the “transmission voice” in (1), the transmission timing is always generated as shown in (3). A mute signal is not output from the switch 43 to the receiver AMP42. Therefore, since the receiver 41 does not receive the mute signal from the PTT switch 43, the audio output remains “ON” as shown in (4). As described above, the handset 40 in duplex communication cannot take measures against “buzzing sound” due to the DC fluctuation occurring at the transmission timing.

  As described above, in the TDMA type radio device 100 according to the conventional example, it is possible to take measures against “buzzing sound” due to DC fluctuation in simplex communication, but to take measures in duplex communication. I can't.

  As a communication technology related to simplex and duplex, there is Patent Document 1 below. In Patent Document 1, full duplex communication is established by providing two voice normal codecs for half-duplex communication, which are low-cost voice codecs, and switching means is provided with one half-duplex voice codec. Thus, by establishing full-duplex communication, a digital mobile radio system capable of duplex communication is provided.

JP-A-2005-347923

  Even with the communication method based on the duplex method of Patent Document 1, full-duplex communication can be established using a half-duplex voice codec. I can't do it. In the conventional technology described above, in the simplex communication using the PTT switch, measures against “buzzing noise” due to DC fluctuations are taken by not outputting audio from a receiver, a speaker, or the like in a transmission state. . However, effective measures have not been taken in duplex communication, and there has been a problem that the communication form must be limited to simplex communication in order to take measures against “buzzing noise” due to DC fluctuation.

  The present invention has been made in view of such a situation, and an object thereof is to provide a wireless system capable of solving the above-described problems.

  The wireless device of the present invention is a TDMA wireless device that performs duplex communication using one frequency, and includes a voice signal input means for inputting a voice signal, and presence / absence of the voice signal input by the voice signal input means. A voice presence / absence detecting means for detecting, a voice output stopping means for stopping the voice output, and a voice output stop releasing means for releasing the stop of the voice output are provided, and the voice presence / absence detecting means does not detect the voice signal. When the voice output is stopped by the voice output stop means, and when the voice presence / absence detecting means detects the voice signal, the voice output is output by the voice output stop release means, so that transmission timing is generated. The output of the voice is stopped in a time zone.

  According to the present invention, it is possible to take measures against an unpleasant “buzzing sound” during voice transmission in duplex communication, and to provide a radio and a voice control method for the radio that improve the communication quality of the radio 100. be able to.

It is a figure which shows the function structure of the audio | voice input / output part of the radio | wireless machine concerning Embodiment 1 of this invention. It is a figure which shows the flow of the voice communication in the duplex call of the radio | wireless machine concerning Embodiment 1 of this invention. It is a figure which shows the function structure of the audio | voice input / output part of the radio | wireless machine concerning Embodiment 2 of this invention. It is a figure which shows the flow of the voice communication in the duplex call of the radio | wireless machine concerning Embodiment 2 of this invention. It is a figure which shows the flame | frame structure of the radio | wireless apparatus concerning the conventional Example. It is a figure which shows the relationship between the transmission timing of the radio | wireless apparatus concerning the conventional Example, and a direct current | flow fluctuation. It is a figure which shows the structure of the radio | wireless machine concerning the prior art and the Example of this invention. It is a figure which shows the function structure of the audio | voice input / output part of the radio | wireless apparatus concerning the conventional Example. It is a figure which shows the flow of the voice communication in the simplex telephone call of the radio | wireless apparatus concerning the conventional Example. It is a figure which shows the flow of the voice communication in the duplex communication of the radio | wireless apparatus concerning the conventional Example.

(First embodiment)
Hereinafter, a first embodiment for carrying out the present invention will be described with reference to the drawings. The first embodiment is a form of duplex communication in which the mute signal output by the PTT switch 55 of the headset 50 in the prior art is performed not by the PTT switch 55 but by VOX (Voice Operation Transmission) that detects received voice. As described above, the first embodiment is a duplex call, in which a call is made with a partner without using a PTT switch.

  The configuration of the wireless device 100a according to the first embodiment of the present invention is the same as that of the wireless device 100 according to the conventional example shown in FIG. 7 except that the headset 50 is changed to the headset 50a. The frame configuration according to the first embodiment of the present invention is the same as the frame configuration in the radio device 100 according to the conventional example shown in FIG.

  Next, a functional configuration of the voice input / output unit 200a that performs voice input / output processing in the wireless device 100a according to the first embodiment will be described. FIG. 1 shows a functional configuration of the voice input / output unit 200a. The audio input / output unit 200a includes a speaker unit 30, a handset unit 40, a headset unit 50a, and an audio codec 70a. The speaker unit 30 and the handset unit 40 are the same as in the conventional example. The headset unit 50a includes a receiver 51, a receiver AMP 52a, a microphone 53, a microphone AMP 54, and a VOX 56. The receiver 51, the microphone 53, and the microphone AMP 54 are the same as in the conventional example. The audio codec 70a is not provided with the PTT switch 55 because the headset unit 50a does not include the PTT switch 55. However, the audio codec 70a is the same as the audio codec 70 of the conventional embodiment except for the site of the headset PTT input unit 75.

  The VOX 56 and the receiver AMP 52a, which are different parts from the wireless device 100 according to the conventional example, will be described. The VOX 56 is a device that detects the presence or absence of an audio signal output from the received audio output unit 71 of the audio codec 70a. The receiver AMP 52 a is a device that outputs a received audio signal to the receiver 51. When the VOX 56 detects an audio signal, the VOX 56 outputs a mute release signal to the receiver AMP 52a. When the receiver AMP 52a of the headset 50a receives the mute release signal from the VOX 56, the receiver AMP 52a releases the mute of the audio output to the receiver 51. When the VOX 56 does not detect an audio signal, the VOX 56 does not output a mute release signal to the receiver AMP 52a. When the receiver AMP 52a of the headset 50a does not receive the mute release signal from the VOX 56, the audio output to the receiver 51 is muted.

  Next, voice communication of the headset 50a in duplex communication according to the first embodiment will be described with reference to FIG. In duplex communication, as shown in (1) and (2) of FIG. 2, a voice signal to be transmitted (transmitted voice) and a voice signal to be received (received voice) are communicated through different communication lines. However, since the transmission voice of (1) and the reception voice of (2) are different communication lines, the transmission voice of (1) is always in the voice transmission time zone. For this reason, transmission timing always occurs as shown in (3). When the VOX 56 detects an audio signal output from the reception audio output unit 71 of the audio codec 70a, the VOX 56 outputs a mute release signal to the receiver AMP 52a. When the VOX 56 does not detect the audio signal output from the reception audio output unit 71 of the audio codec 70a, the VOX 56 does not output the mute release signal to the receiver AMP 52a. Become. Thus, the audio output of the receiver 51 of (4) is set to “ON” only in the time zone of “Received audio” in (2), but the audio of the receiver 51 is in the time zone of “Transmission audio” in (1). Since the output is “off”, it is possible to take measures against “buzzing noise” due to a DC fluctuation occurring at the transmission timing.

  In the first embodiment described above, there may be a slight delay until the VOX 56 detects the audio signal and turns off the audio output of the receiver 51. This slight delay can be solved by confirming with a predetermined wording before entering a call before starting a call.

  According to the first embodiment as described above, the audio output of the receiver 51 is normally “off” and nothing can be heard by the user's ear, but when the audio is received from the other party, the audio signal is output. By detecting the VOX 56, the audio output of the receiver 51 can be turned on. In this way, since it is possible to take measures against an unpleasant “buzzing sound” during voice transmission in a duplex call, the headset can be used in a reverse call. In addition, the communication quality of the radio device 100a can be improved.

(Second Embodiment)
Hereinafter, a second embodiment for carrying out the present invention will be described with reference to the drawings. The second embodiment is a duplex communication mode in which the mute signal output from the PTT switch 55 of the headset 50 in the prior art is output at the transmission timing change point. As described above, the second embodiment is a duplex call, in which a call is made with the other party without using the PTT switch.

  The configuration of the wireless device 100b according to the second embodiment of the present invention is the same as that of the wireless device 100 according to the conventional example shown in FIG. 7 except that the headset 50 is changed to the headset 50b. The frame configuration according to the second embodiment of the present invention is the same as the frame configuration in the radio device 100 according to the conventional example shown in FIG.

  Next, a functional configuration of the voice input / output unit 200b that performs voice input / output processing in the wireless device 100b according to the second embodiment will be described. FIG. 3 shows a functional configuration of the voice input / output unit 200b. The audio input / output unit 200b includes a speaker unit 30, a handset unit 40, a headset unit 50b, and an audio codec 70a. The speaker unit 30 and the handset unit 40 are the same as in the conventional example. The headset unit 50 b includes a receiver 51, a receiver AMP 52, a microphone 53, a microphone AMP 54, and a mute timing generation unit 58. A wireless unit 57 is connected to the mute timing generator 58. The receiver 51, the receiver AMP52, the microphone 53, and the microphone AMP54 are the same as those in the conventional example. The audio codec 70a is the same as the audio codec 70a of the first embodiment, and the headset unit 50b does not include the PTT switch 55. Therefore, the site of the headset PTT input unit 75 is not provided. This is the same as the audio codec 70 of the embodiment.

  The wireless unit 57 and the mute timing generating unit 58, which are different parts from the wireless device 100 according to the conventional example, will be described. The wireless unit 57 is a device that detects the change point of the transmission timing shown in FIG. 6 in the wireless device 100 b and outputs it to the mute timing generation unit 58. When the mute timing generator 58 receives the transmission timing change point from the radio unit 57, the mute timing generator 58 outputs a mute signal to the receiver AMP 52. Further, the mute timing generator 58 does not output a mute signal to the receiver AMP 52 when the transmission timing change point is not output from the radio unit 57.

  Next, voice communication of the headset 50b in duplex communication according to the second embodiment will be described with reference to FIG. An enlarged view of the transmission timing in (3) is shown in (3) ′, and an enlarged view of the audio output of the receiver 51 in (4) is shown in (4) ′. In duplex communication, as shown in (1) and (2) of FIG. 4, a transmitted voice signal (transmitted voice) and a received voice signal (received voice) are communicated through separate communication lines. However, since the transmission voice of (1) and the reception voice of (2) are different communication lines, the transmission voice of (1) is always in the voice transmission time zone. For this reason, transmission timing always occurs as shown in (3). Since the mute timing generator 58 of the headset 50b outputs a mute signal to the receiver AMP 52 at the transmission timing change point (3), the audio output of the receiver 51 (4) is “off” at the transmission timing change point. " Further, since the mute timing generator 58 of the headset 50b does not output a mute signal to the receiver AMP 52 except for the change point of the transmission timing in (3), the audio output of the receiver 51 in (4) is the change point of the transmission timing. Otherwise, it is “ON”. Thus, even if the transmission timing of (3) occurs in the “transmission voice” time zone of (1), the audio output of the receiver 51 of (4) is changed to “ By setting it to “OFF”, it is possible to take measures against “buzzing noise” due to DC fluctuations caused by changes in transmission timing.

  According to the second embodiment as described above, the mute timing generation unit 58 performs the audio of the receiver 51 at the changing point from the transmission timing signal output from the radio unit 57 to transmission / reception / standby and reception / standby to transmission. The output can be “off” for a short time. In this way, since it is possible to take measures against an unpleasant “buzzing sound” during voice transmission in a duplex call, the headset can be used in a reverse call. Further, the communication quality of the radio device 100b can be improved.

  In the first embodiment and the second embodiment, the headset that is easily affected by “buzzing noise” in order to put the receiver on the ear has been described. However, the present invention can also be applied to a speaker or a handset. In the first embodiment and the second embodiment, the example applied to the case where there is one headset has been described. However, a plurality of headsets, speakers, handsets, and the like may exist.

  As mentioned above, although this invention was demonstrated by specific embodiment, it cannot be overemphasized that the said embodiment is an illustration of this invention and is not limited to this embodiment.

In summary, the present invention has the following characteristics.
(1) The wireless device of the present invention is a TDMA wireless device that performs duplex communication using one frequency, and includes an audio signal input unit that inputs an audio signal, and the audio signal that the audio signal input unit inputs. Voice presence / absence detection means for detecting the presence / absence of voice, voice output stop means for stopping the output of voice, and voice output stop cancellation means for releasing the stop of voice output, wherein the voice presence / absence detection means is the voice signal. When the voice output is stopped by the voice output stop means, the voice output is stopped by the voice output stop means, and when the voice presence / absence detection means detects the voice signal, the voice output is stopped by the voice output stop release means. The voice output is stopped during the voice transmission time zone.
(2) The voice presence / absence detecting means of (1) is a VOX.
(3) The voice stop means and the voice stop release means of (1) or (2) are means for muting or releasing the output of the receiver AMP.
(4) The wireless device of the present invention is a TDMA wireless device that performs duplex communication using one frequency, and includes transmission timing input means for inputting transmission timing and the transmission timing input by the transmission timing input means. A change point detecting means for detecting a change point from the sound and a sound output stop means for stopping the output of the sound, and the sound output stop when the change point detecting means detects the change point of the transmission timing. The output of the sound is stopped by the means.
(5) The voice stop means of (4) is characterized in that the output of the voice is stopped by a receiver AMP.
(6) The voice control method of the radio of the present invention is a TDMA radio that performs duplex communication using one frequency, and the voice signal input step for inputting a voice signal and the voice signal input step for input A voice presence / absence detecting step for detecting the presence / absence of the voice signal, a voice output stop step for stopping the voice output, and a voice output stop releasing step for releasing the stop of the voice output. When the voice signal is not detected, the voice output is stopped by the voice output stop step, and when the voice presence / absence detection step is detected the voice signal is output by the voice output stop release step, The voice output is stopped in a voice transmission time zone in which transmission timing occurs.
(7) A voice control system for a radio of the present invention is a voice control system for a TDMA radio that performs duplex communication using one frequency, and includes a transmission timing input step for inputting a transmission timing, and the transmission timing. A change point detection step of detecting a change point from the transmission timing input in the input step; and a voice output stop step of stopping voice output, wherein the change point detection step detects the change point of the transmission timing. Sometimes, the voice output is stopped by the voice output stop step.

  The present invention is suitable for a wireless device, but is not limited to a wireless device, and can be applied to general systems that are affected by radio wave coverage caused by intermittently transmitting radio waves.

10 ... Radio equipment 20 ... Antenna 30 ... Speaker 31 ... Speaker 32 ...・ Speaker AMP
・ ・ ・ ・ ・ ・ ・ ・ Handset 41 ・ ・ ・ ・ ・ ・ ・ ・ Receiver 42 ・ ・ ・ ・ ・ ・ ・ ・ Receiver AMP
43 ... PTT switch 44 ... Microphone 45 ... Microphone AMP
50 ..... Headset 50a ..... Headset 50b ..... Headset 51 ..... Receiver 52 ........... Receiver AMP
53 ... Mic 54 ... Mic AMP
55 ... PTT switch 56 ... VOX
57... Wireless section 58... Mute timing generation section 70... Audio codec 70 a... Audio codec 71. ········································· 72 .... Headset PTT input unit 100 ... Radio 100a ... Radio 100b ... Radio 200 ... ..Voice input / output unit 200a ... Voice input / output unit 200b ... Voice input / output unit

Claims (1)

A TDMA type radio that performs duplex communication using one frequency,
An audio signal input means for inputting an audio signal;
Voice presence / absence detection means for detecting the presence or absence of the voice signal input by the voice signal input means;
Audio output stop means for stopping output of audio;
Voice output stop cancellation means for canceling the stop of the output of the voice,
When the sound presence / absence detection means does not detect the sound signal, the sound output stop means stops outputting the sound, and when the sound presence / absence detection means detects the sound signal, the sound output stop release means stops the sound output. By outputting, the radio is stopped during the voice transmission time zone in which the transmission timing occurs.

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